I2P support forum

In linux you can do some generic performance tweaks that also improve MW's speed.

1) sysctl vm.swappiness=0 (reduce swapping to a minimum)
2) sysctl vm.vfs_cache_pressure=1 (cache read io as much as possible)
3) use ext4 noatime and nodiratime options to disable read logging

You can also increase the number of i2p tunnels in the MW Options menu.
The default is 4in + 4out at 3hops length.